Keyboard locking means



g- 3, 1939- K. R. SCHNEIDER AL 2,168,423

KEYBOARD LOCKING MEANS Filed Nov. 11, 1937 2 Sheets-Sheet l INV NTORS ml 5 z M ATTORNEY g 1939- K. R SCHNEIDER ET AL 2 KEYBOARD LOCKING MEANS- Filed Nov. 11, 1937 2 Sheets-Sheet 2 FIG. 3.

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ATTORNEY Patented Aug. 8, 1 939 UNITED STATES KEYBOARD LOCKING DIEANS Kurt R. Schneider and Clyde J. Fitch, Endicott, N. Y., assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York Application November 11, 1937, Serial No. 174,018

7 Claims. (Cl. 178-74) -'This invention relates to keyboard. locking mechanisms jor recording units and is particularly applicable to 'printing telegraph systems utilizing key operated devices to initiate thecharacter signals.

An object of the present invention is to'provide time delay means to cooperate with a positionable keyboard locking means, so that upon operation of a control switch the signaling apparatus of the system is conditioned before any of the character keys can be operated, and upon conditioning of the. said apparatus the time delay means is rendered operative to release the character key bars for signaling functions.

Another object of the invention is to provide electronic control means for controlling the operationoi the keyboard locking means.

Further objects of the: instant invention reside in any novel feature of construction or operation or novel combination of parts present in the embodiment of the invention described and shown in the accompanying drawings whether withinor without the scope of the appended claims and irrespective of other specific statements as to the scope of the invention contained herein.

In the drawings:

Fig. 1 is a sectionalview of one type of recording unit.

' Fig. 2 is an exploded view of the cam unit. In this figure certain structural details are exaggerated to show clearly the normal relationship of certain elements.

Fig. 3 shows diagrammatically one type of signaling system. utilizing the present invention.

Fig. 4 shows diagrammatically one form of a keyboard loclgmechanism.

For illustrative purposes, this invention is shown as embodying a well known type of recording unit, which may be similar in construction to the Electromatic typewriter, shown and described in detail in U, S. iatent No. 1,777,055, and nence requires only the following brief descripion. e Referring to the drawings and particularly to Fig. 1,- well known means are provided for actuating the type bars Iii, comprising a constantly rotating roller l0, cooperating with a series of individual power units each comprising a cam ii, the engagement of the cams with the roller being controlled selectively by the character key bars i'l.

Any suitable means may be provided to rotate the power roller, in the direction indicated by the arrow, which is adapted to cooperate with two rows of cam units arranged in the front and rear of the roller.- The cam it may be provided ence character IS, the other arm of the said bell crank lever is operatively connected with an arm of hell crank lever II by means of link l5. Another arm of the said lever I4 is connected to the type bars IS in. a well known manner, so asto effect operation of the type bars or any other suitable means connected to the bell crank levers upon selective operation of the controlling key bars I'I.

The pivoted-bell crank lever I2 is operated by the associated cam ll whenever the latter engages the driven roller; the engagement of the cam with the roller is controlled by means oi .position, and tends to turn the cam H in a clockwisedirection. This is prevented, however, by the engagement of one of the detents 2| on the cam, with the upper stop lug 22 on the stop lever 23. If, however, the corresponding key bar is operated, the bifurcated lower end (Fig. l) of extension arm. 24 associated with one of the said key bars l1 engages an arm 25 at the upper end of the stop lever 23 which is provided with an offset projection at its end which extends laterally through an opening in the bell crank lever i2. The arm 25 of the stop lever 23 is then swung rearwardly or to the left as viewed in Fig. 1 about the pivot 26 and its lower end forwardly or to the right as viewed in this figure, thus releasing the cam, which then turns under the influence of the spring urged impeller-arm iii. In doing so the upper serrated lobe of the cam is brought into engagement with the power roller, which turns in a counterclockwise direction and therefore causes a continued rolling movement of the cam until the high point has been reached and passed. This causes the whole cam unit to swing around the pivot l3 so as to pull down the corresponding link and actuate one of the type bars or any other mechanism with which the cam unit may be connected.

of cam il until the second detent'2l-engages one 'of the stop lugs. Since the half rotation of the cam consumes only a small fraction of a second,

it is diflicult to release the key bar within this short interval, so that it is the lower lug 28 which is first ,engaged, but upon the release of the key bar. and the return of the stoplever 23 to normal position, lug 28 disengages the detent, whereupon the impeller-arm rotates the cam slightly, and the said detent then engages the upper stop ing 22.

It-is obvious then that depression of a key bar releases the revolubly mounted cam to engage and be actuated by the power roller in turn operating the associated bell crank lever and its attached links to cause the associated mechanism such as the type bars and other operating mechanisms, to be operated. It is to be understood that an individual cam unit is provided for each type bar or other functional mechanisms associated therewith.

The action of the cam mechanism has been described with respect to oneof the rear bank of cam units; in the case of those of the forward bank the operation is analogous, but the directions of movement, and the order of operation of the stop lugs, is reversed. For example, if the bifurcatedarm 24-a is positioned to engage the arm af at the upper end of stop lever 23a by virtue of operation of the associated key bar, the said arm is positioned rearwardly or to the left as viewed in Fig. l, and the lower end of the stop lever 23a is moved forwardly, that is, to the right as viewed in the said figure. This said operation is effective to release the cam, by virtue of positioning the lower stop lug 28-a out of the path of detent 2la, thus permitting the springurged impeller arm I 8-41 to rotate the cam slightly in a clockwise direction to efi'ect engagement of the lower. lobe of cam II and power roller. Upon completion of a half revolution of the cam I I, the second detent Z'I-a engages first the upper stop lug 22a while the stop lever 23a is in an operated position, but upon release of the associated key bar and the return of the said stop lever to normal position, this lug 22-a disengages the said detent and the impeller-arm rotates the cam slightly so that the said detent tnen engages the lower stop lug 28-41, as shown in the figure. Inthis manner the bell crank lever l2a is rotated about the pivot I3a to operate the associated type bar or any other mechanism associated therewith. For further structural details of the cam units, reference should be made to the above mentioned patent.

In addition to operating the described cam units, the releasing of the cams II by the key bars I1 is effective to operate the contacts 30 which are suitably disposed so as to be engaged by the associated cams. The said contacts may be embodied in any of the known signaling systems to initiate impulses representing the characters. In Fig. 3, a simplified circuit diagram of a suitable signaling system is shown in combination with the present invention. The individual contacts 30 are shown to be'connected in the input circuits of individual tube oscillator systems 3| which are shown diagrammatically and need not be described in detail since suitable tube oscillators are old and well known in the art. One form of tube oscillator, for example, is shown in the U. S. Patent No. 1,661,962. Each oscillator system is arranged and adjusted to generate different frequencies which when impressed upon the transmission circuit may be representative of signal conditions for the different characters. The output circuits of the saidoscillators are shown to be connected to suitable filters 32 adapted to pass only the frequency generated by the associated oscillator. The filters are then shown to be connected to a suitable amplifier and signal transmitter indicated generally by the reference character 33, which is not shown or described in detail since many suitable types are well known, one form of which is shown and described in the said last mentioned patent. The only purpose in showing the signaling system described is to illustrate a form of signal generating means using thermionic tubes, the operation of which is controlled by the signal initiating means, namely, the contacts 30 and controlling key bars and cam units, and showing the relationship of the filament or filament heater voltage supply of the signal generating or transmitting means with respect to the filament circuit of the time delay electronic means used to control the operation of the keyboard locking device. For this reason, the individual filament circuits of the oscillators, amplifier and transmitter'ar shown connected by a common circuit '34 to a common source of supply 35 through a control switch 36. To those skilled in theart, the application of the present invention is evident and for this reason it is believed that the brief foregoing description of the signaling system is sufiicient, particularly since the signaling system per se is not claimed.

The filament heater of the time delay tube 31 is also shown to be connected to the common filament supply source 35 and is shown to include a resistor 38 in the circuit. The plate of the said tube is connected to one terminal of the relay coil 39, the other terminal of which is connected to the positive terminal of the plate supply source. The normally open contacts 40 controlled by relay coil 39 are connected to a power source and magnet coil 4], so that upon energizatlon of the tube 31 the relay 39 is operated to energize the control magnet 4|. It is evident now from the description just set forth, that shortly after operation of the control switch 36 the tubes associated with the signal generating and transmitting means are conditioned so as to be rendered operative so that the signaling system controlled'by the signal initiating means 30 is in a condition for operation. To be assured that the contacts 30 or signal initiating means can not be operated before the tubes of the signaling systems have been given sufficient time to be properly conditioned so as to function properly, thetime delay tube 31 and the associated circuits are provided to control the release of the controlling key bars. The resistor 38 is inserted in the filament heater circuit of the tube 31 so that the supply source which is shown common to all the filament or filament heater circuits is not effective to render the tube 31 operative or in a condition for operation at the same time the other tubes of the described circuit are rendered operative or in a condition to be operated. A time delay of the order of thirty seconds, for example, may be sufficient time for the tubes in the signaling circuit to be conditioned for operation, therefore the value of the resistor 38 is adjusted to delay the operation of the tube 31 to this extent. The operation of the relay 3! and magnet 4| similarly is delayed, the period of delay depending upon the value of the resistor 38.

With reference now to Fig. 4, the magnet 4| is shown to have the armature associated therewith linked or associated with a locking bar 42 cooperating with the key bars I! and suitably mounted on the key bar guide comb 43 of the recording unit. Referring to Fig. 1, the key bar comb 43 is shown to be disposed and arranged to cooperate with the forward extremities of the key bars. The forward extremities or extensions of each of the key bars are arranged to extend through or into the individual slots 44 in the comb 43. Clamps 45 or any other suitable means are provided to hold the locking bar 42 in position beneath the key bar extensions. Elongated openings 46 are provided in the said bar so as to be slidably mounted on the comb. The studs or screws 41 secured to clamps 45 extend through the openings 46 and thus limit the movement of the locking bar. A spring 48 is attached to the locking bar and one of the clamps 45 so that normally the said spring holds the locking bar in the position shown in the figure. position the individual sections 49 of the locking bar are positioned directly under the individual key bars 11, thus preventing the key bars to be depressed at any time. However, upon energization of the magnet 4|, the link 50 is positioned to the left as viewed in the figure against the tension of the spring 48 to position the slidable locking bar 42 to the left, so that the sections 49 no longer block the action of the key bars, but

permit the individual key bars I'I to'be depressed to the extent so as to release the associated cam units.

The locking bar positioning magnet 4| is shown to be controlled by the time delay tube 31 and therefore it is understood that in this manner the signaling apparatus can be definitely conditioned for signal transmission purposes before the operator can begin to operate the signal initiating means, namely, the key bars and associated cam controlled contacts.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is as follows:

1. A system of the character described comprising a keyboard having a plurality of operable key bars, key bar locking means comprising a positionable bar, means tomaintain the said bar in one position engaging the key bars and thereby preventing them from being operated, control means, and means adapted to be energized for a predetermined time interval for rendering the control means effective to control the positioning of the said bar thereby releasing the said key bars.

2. A system of the character described comprising a keyboard having a plurality of operable key bars, key bar locking means comprising a slidable bar cooperating with the individual key bars, spring means adapted to maintain the said bar in a normal position engaging the key bars thereby preventing their being operated, control means comprising a thermionic tube and electromagnetic device controlled thereby, said electromagnetic device including means for positioning the sildable bar when operated by the thermionic tube thereby releasing the key bars, and means adapted to be energized for a predetermined timed interval to render the said thermionic tube operative.

3. In a system of the character described, teleprinter signal initiating means comprising key bars and signal generating means controlled thereby, switching means for conditioning the Inthis' signal generating means including means whereby the signal generating means is adapted to be iri condition for operation by the signal initiating means, key bar controlling means normally maintaining the key bars inoperative, and time delay means controlled by the operation ofthe switching means including means whereby the time delay means is adapted to be operated a predetermined time interval after operation of said switching means, said keyv bar controlling means controlled by the operated time delay means to release the key bars thereby rendering them operative to control the signal generating means.

4. In a system of the character described, signal transmission means and signal initiating .means including a plurality of operable key bars,

operable control means to render the signal transmission means operative and in a condition to be operated by the signal initiating means, locking means associated with the key bars normally rendering the key bars inoperative, and means controlled by the said control means to operate the locking means a predetermined-time interval after operation of the said control means and means included in the locking means for releasing the key bars upon operation of the locking means, for operation,

5. In a system of the character described, signal transmitting means including thermionic means and a voltage supply source therefor, teleprinter means comprising operable key bars to control the operation of the signal transmitting means, locking means to normally render the key bars inoperative, means to connect the voltage supply to the signal transmitting means, and means to operate the said locking means rendering the key bars operative a predetermined time interval after operation of the said means connecting the said supply to the signal transmitting means.

6. In a system of the character described, signal transmitting means including thermionic means, teleprinter means comprising operable key bars to control the operation of the signal transmitting means, locking means to normally render the key bars inoperative, control means to control the operation of the locking means including thermionic means, a voltage supply source for said thermionic means, switching means to connect the said voltage supply source to the thermionic means, and means associated with the second mentioned thermionic means to render it operative a predetermined time interval after the first mentioned thermionic means are rendered operative by the voltage supply thereby rendering the control means operative to operate the locking means and render the key bars operative.

7. A system of the character described comprising a plurality of controlling key bars and locking means therefor normally rendering them inoperative, means including thermionic means to control the operation of the said locking means, a voltage supply source for said thermionic means and switching means to connect said source to the thermionic means, and means to render the thermionic means operative a pre- 

